Quercetin prevents oxidative stress in cirrhotic rats.

Our aim was to study the protective effect of quercitin on liver cirrhosis induced by carbon tetrachloride (CCl(4)) in rats and its relationship with liver morphology. Thirty male Wistar rats weighing 200-250 g were randomly divided into three groups: control, CCl(4), and CCl(4)+ quercetin. Rats in the experimental groups were given CCl(4) (0.5 ml/kg i.p.), diluted 1:6 in vegetable oil (5 mmol/kg body wt), at 10:00 p.m. every 4 days for 17 weeks. Quercetin (500 microl/kg i.p.; 150 micromol/kg body wt) or vehicle was administered at 6:00 p.m. for the last 3 weeks of the study. Control group rats were given only olive oil for the same period. At the end of the 17 weeks, all rats were sacrificed. Blood samples were taken for determination of serum indicators (ALT, AST, total bilirubin, conjugated bilirubin, factor V) and the livers were dissected out and divided into two parts: one was homogenized and the supernatant was used for measurement of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) activities, as well as lipid peroxidation. The other part was used for the histopathological study. CCl(4) caused a marked rise in serum levels of ALT, AST, total bilirubin, and conjugated bilirubin, as well as a decrease in factor V (P<0.05). Lipid peroxidation levels were significantly increased, whereas GSH, SOD, catalase, GPx, and GST levels were decreased in the liver of CCl(4)-treated rats. Quercetin (50 mg/kg/day) successfully attenuated these effects of CCl(4). We conclude that quercetin has beneficial effects on liver fibrosis in rats by enhancing antioxidant enzyme activity and decreasing the pro-oxidant effect.